src/test/compile-fail/associated-type-projection-from-multiple-supertraits.rs

   1 // Copyright 2014 The Rust Project Developers. See the COPYRIGHT
   2 // file at the top-level directory of this distribution and at
   3 // http://rust-lang.org/COPYRIGHT.
   4 //
   5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
   6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
   7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
   8 // option. This file may not be copied, modified, or distributed
   9 // except according to those terms.
  10
  11 // Test equality constraints in a where clause where the type being
  12 // equated appears in a supertrait.
  13
  14 pub trait Vehicle {
  15     type Color;
  16
  17     fn go(&self) {  }
  18 }
  19
  20 pub trait Box {
  21     type Color;
  22
  23     fn mail(&self) {  }
  24 }
  25
  26 pub trait BoxCar : Box + Vehicle {
  27 }
  28
  29 fn dent<C:BoxCar>(c: C, color: C::Color) {
  30     //~^ ERROR ambiguous associated type `Color` in bounds of `C`
  31     //~| NOTE ambiguous associated type `Color`
  32     //~| NOTE could derive from `Vehicle`
  33     //~| NOTE could derive from `Box`
  34 }
  35
  36 fn dent_object<COLOR>(c: BoxCar<Color=COLOR>) {
  37     //~^ ERROR ambiguous associated type
  38     //~| ERROR the value of the associated type `Color` (from the trait `Vehicle`) must be specified
  39     //~| NOTE ambiguous associated type `Color`
  40     //~| NOTE could derive from `Vehicle`
  41     //~| NOTE could derive from `Box`
  42     //~| NOTE missing associated type `Color` value
  43 }
  44
  45 fn paint<C:BoxCar>(c: C, d: C::Color) {
  46     //~^ ERROR ambiguous associated type `Color` in bounds of `C`
  47     //~| NOTE ambiguous associated type `Color`
  48     //~| NOTE could derive from `Vehicle`
  49     //~| NOTE could derive from `Box`
  50 }
  51
  52 pub fn main() { }